Messages in this thread Patch in this message | | | Date | Wed, 8 Nov 2023 00:46:26 -0500 | Subject | Re: [PATCH] drm/sched: fix potential page fault in drm_sched_job_init() | From | Luben Tuikov <> |
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Hi,
Could you please use my gmail address, the one one I'm responding from--I don't want to miss any DRM scheduler patches. BTW, the luben.tuikov@amd.com email should bounce as undeliverable.
On 2023-11-07 21:26, Danilo Krummrich wrote: > Commit 56e449603f0a ("drm/sched: Convert the GPU scheduler to variable > number of run-queues") introduces drm_err() in drm_sched_job_init(), in > order to indicate that the given entity has no runq, however at this > time job->sched is not yet set, likely to be NULL initialized, and hence > shouldn't be used. > > Replace the corresponding drm_err() call with pr_err() to avoid a > potential page fault. > > While at it, extend the documentation of drm_sched_job_init() to > indicate that job->sched is not a valid pointer until > drm_sched_job_arm() has been called. > > Fixes: 56e449603f0a ("drm/sched: Convert the GPU scheduler to variable number of run-queues") > Signed-off-by: Danilo Krummrich <dakr@redhat.com> > --- > drivers/gpu/drm/scheduler/sched_main.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c > index 27843e37d9b7..dd28389f0ddd 100644 > --- a/drivers/gpu/drm/scheduler/sched_main.c > +++ b/drivers/gpu/drm/scheduler/sched_main.c > @@ -680,6 +680,9 @@ EXPORT_SYMBOL(drm_sched_resubmit_jobs); > * This function returns -ENOENT in this case (which probably should be -EIO as > * a more meanigful return value). > * > + * Note that job->sched is not a valid pointer until drm_sched_job_arm() has > + * been called. > + *
Good catch!
Did you actually get this to page-fault and have a kernel log?
I'm asking because we see it correctly set in this kernel log coming from AMD,
[ 11.886024] amdgpu 0000:0a:00.0: [drm] *ERROR* drm_sched_job_init: entity has no rq!
in this email, https://lore.kernel.org/r/CADnq5_PS64jYS_Y3kGW27m-kuWP+FQFiaVcOaZiB=JLSgPnXBQ@mail.gmail.com
> * Returns 0 for success, negative error code otherwise. > */ > int drm_sched_job_init(struct drm_sched_job *job, > @@ -691,7 +694,7 @@ int drm_sched_job_init(struct drm_sched_job *job, > * or worse--a blank screen--leave a trail in the > * logs, so this can be debugged easier. > */ > - drm_err(job->sched, "%s: entity has no rq!\n", __func__); > + pr_err("%s: entity has no rq!\n", __func__);
Is it feasible to do something like the following?
dev_err(job->sched ? job->sched->dev : NULL, "%s: entity has no rq!\n", __func__);
> return -ENOENT; > } > > > base-commit: c015fb6d01adb616fb54824feb55ce5ab18e8ca1
-- Regards, Luben [unhandled content-type:application/pgp-keys][unhandled content-type:application/pgp-signature] | |